"We have to deal with IS based on the wider threat they pose to the British public, as well as to this individual.

"It doesn't make any difference at all to our strategic planning. As the Prime Minister said, we will look very carefully at the options available to us to support the legitimate government of Iraq and Kurdistan in defending themselves from (IS).

"If we judge that air strikes could be beneficial, could be the best way to do that, then we will certainly consider them but we have made no decision to do so at the moment."